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  2. Luminosity - Wikipedia

    en.wikipedia.org/wiki/Luminosity

    A star also radiates neutrinos, which carry off some energy (about 2% in the case of the Sun), contributing to the star's total luminosity. [5] The IAU has defined a nominal solar luminosity of 3.828 × 10 26 W to promote publication of consistent and comparable values in units of the solar luminosity. [6]

  3. Sun - Wikipedia

    en.wikipedia.org/wiki/Sun

    The Sun is 1.4 million kilometers (4.643 light-seconds) wide, about 109 times wider than Earth, or four times the Lunar distance, and contains 99.86% of all Solar System mass. The Sun is a G-type main-sequence star that makes up about 99.86% of the mass of the Solar System. [26]

  4. Glossary of astronomy - Wikipedia

    en.wikipedia.org/wiki/Glossary_of_astronomy

    A-type star In the Harvard spectral classification system, a class of main-sequence star having spectra dominated by Balmer absorption lines of hydrogen. Stars of spectral class A are typically blue-white or white in color, measure between 1.4 and 2.1 times the mass of the Sun, and have surface temperatures of 7,600–10,000 kelvin.

  5. Apparent magnitude - Wikipedia

    en.wikipedia.org/wiki/Apparent_magnitude

    star Sun: seen from Venus at perihelion −26.832: star Sun: seen from Earth [16] about 400,000 times as bright as mean full Moon −25.60: star Sun: seen from Mars at aphelion: −25.00: Minimum brightness that causes the typical eye slight pain to look at: −23.00: star Sun: seen from Jupiter at aphelion −21.70: star Sun: seen from Saturn ...

  6. List of most luminous stars - Wikipedia

    en.wikipedia.org/wiki/List_of_most_luminous_stars

    The first star in the list, Godzilla [1] — an LBV in the distant Sunburst galaxy — is probably the brightest star ever observed, although it is believed to be undergoing a temporary episode of increased luminosity that has lasted at least seven years, in a similar manner to the Great Eruption of Eta Carinae that was witnessed in the 19th ...

  7. Standard solar model - Wikipedia

    en.wikipedia.org/wiki/Standard_solar_model

    Along with this abundance information, a reasonable guess at the zero-age luminosity (such as the present-day Sun's luminosity) is then converted by an iterative procedure into the correct value for the model, and the temperature, pressure and density throughout the model calculated by solving the equations of stellar structure numerically ...

  8. Mass-to-light ratio - Wikipedia

    en.wikipedia.org/wiki/Mass-to-light_ratio

    The luminosity thus obtained is known as the bolometric luminosity. Masses are often calculated from the dynamics of the virialized system or from gravitational lensing . Typical mass-to-light ratios for galaxies range from 2 to 10 ϒ ☉ while on the largest scales, the mass to light ratio of the observable universe is approximately 100 ϒ ...

  9. Absolute magnitude - Wikipedia

    en.wikipedia.org/wiki/Absolute_magnitude

    Following Resolution B2, the relation between a star's absolute bolometric magnitude and its luminosity is no longer directly tied to the Sun's (variable) luminosity: = ⁡ ⁡ + where L ★ is the star's luminosity (bolometric luminosity) in watts